Severity: Moderate
Drivable, but it can cause more damage or poor economy. Get it checked within days.
What P0172 means
Bank 1 is running rich: the computer is pulling fuel out and still sees too much.
Symptoms
- Black smoke or fuel smell
- Poor fuel economy
- Fouled plugs
Common causes
Most likely first
- 1Leaking fuel injector
- 2High fuel pressure / failed regulator
- 3MAF sensor reading high
- 4Fuel in the oil (crankcase vapor)
- 5Restricted air filter
How we diagnose it
- Fuel trims
- Fuel pressure and leak-down test
- MAF data check
- Smell oil for fuel
Every vehicle sets codes under its own conditions. We check the factory diagnostic steps and service bulletins for your VIN, so the repair targets the actual cause.